My EF Fairmont GHIA is idling poorly and cutting out.

When we removed the PCV valve from my mates EF it sucks loudly and mine sucks gently. We removed the air filter, checked everything. Removed the PCV and blew in it but no apparent leaks.

EF has an error code 786 PERFORMANCE INDICATOR LAMP . 786 is not in my manual and I do not know what this is. Grrrrrrrrrrrrrrrrrrrr.....

Michael